Professionals call for state to reject new 520 bridge pontoons
SEATTLE -- Professionals are calling for the state to reject the first six pontoons built for the new 520 Floating Bridge. Last week a KOMO 4 Problem Solver investigation revealed that all six pontoons had leaks. Now we've uncovered new safety concerns about those pontoons breaking apart during a severe storm.
"We did not have leaks. We did not have cracks," says Jerry Purdum, a retired engineer. His first big job was the original 520 bridge building pontoons from 1960 to 1963.
Purdum says even 50 years ago the pontoons they built, massive at 360 feet long, had no cracks and no leaks. "They never took on water," says Purdum, "they never had a leak." So now, Purdum can't understand how or why Washington's Department of Transportation is having so many problems with the first six pontoons.
A Problem Solver investigation revealed last week that all six pontoons had leaks. Even leaking through, in some cases, extensive repairs.
Purdum says as a professional and as a taxpayer, he's concerned.
"What are they going to do with those six pontoons? They're allowing them to bolt them up in the lake now. They're not gonna be rejected?" he said. When we ask if they should be rejected his answer is adamant: "Yes. Because they're leaking."
A WSDOT insider who asked to remain anonymous also believes that, like Purdum, the state should reject all six of the first pontoons and tell contractor Kiewit in Aberdeen to start over. Purdum adds, "This is not a typical girder or bridge beam holding up a flat slab on ground; this is a floating structure. I think this is wrong."
Now the Problem Solvers have uncovered a new structural problem buried in thousands of documents we obtained through the Public Records Act: The type of structural weakness that could be as catastrophic as WSDOT's own animation from 2007 depicting how the old bridge might come apart in a severe windstorm. The key is the joints between pontoons and how they are connected with rebar called Hook Bars.
Internal WSDOT e-mails from last spring show that structural rebar in Pontoon V was "missing". WSDOT's own engineer Patrick Clarke noted that he could not "structurally approve it" without those essential pieces. In spite of that, documents show that contractor Kiewit opted to ignore Clarke's recommendations for repair, and quote "proceed at risk".
Kiewit went on to do the same with the two other large pontoons so all three now on the lake are missing that critical rebar. A second WSDOT engineer also found this was "not structurally acceptable." Documents and our insider also indicate that, just like in the WSDOT animation, the loss of that critical rebar would weaken the joints by as much as 50 percent, and could cause a similar "unravelling" in a severe, 100 year, windstorm event.
"They've got some problems," Purdum said. "They should find out what it is and solve it before they continue placing pontoons."
Late Thursday, the state told us it is working with Kiewit and that if the missing rebar requires retrofitting, it will be done along with any other necessary repairs to ensure pontoons that will last for 75 years.
On several occasions KOMO 4 News has asked WSDOT to let us speak directly with key engineers who've been critical of how the project is progressing, including Patrick Clarke quoted from documents in this article. But WSDOT says it's not appropriate for employees to discuss issues that are currently under review.